Levulinic acid production through two-step acidic and thermal treatment of food waste using dilute hydrochloric acid

Abstract

This research investigated the concept of a two-step acidic and thermal treatment for glucose extraction and levulinic acid (LA) production from food waste using dilute hydrochloric acid (DHA) as a catalyst, and subsequently analyzed the properties of the resulting humins. Glucose extraction was performed under various reaction conditions (reaction temperature range: 120-190 °C, DHA concentration range: 0.2-0.5% v/v); the glucose extraction yield of the acidic treatment step reached 83.17% under the optimal conditions (150 °C in 0.5% DHA). LA production was achieved during the thermal treatment step, which was investigated using two independent experiments to determine the influence of the reaction conditions (reaction time: 5-140min, concentration factor: 1.5-3.0, reaction temperature: 160-190 °C). The LA production process was affected by the concentration factor and the reaction temperature due to the low pH of solution and the rapid reaction rate, respectively. The thermal stability of the humins was highest at a concentration factor of 3.0 because of the 13.07 C/H ratio of the humins.